Ellipsograph.



' PATENTED JAN. 28, 190s.

1?. u. GOODAL E. ELLIP'SOGRAPH. APPLICATION TILED APR.13 .190'/. j

m m (m I tance UNITED STATES PATENT OFFICE.

FRANK R. GOODALE, OF EXETER, NEW HAMPSHIRE.

ELLIPSOGREPH:

Specification of Letters Patent.

Patented Jan. 28, 1908.

Application filed April 13- 1907. Serial No. 368-016.

The present invention relates to improvements in ellipsogra hs, and it aims to provide an extremely simp e and efficient instrument of that type, by means of which ellipses of different curvatures may be readily and quickly described.

'To this end, the invention resides in the provision of an elliptical dial having a T- shaped, vertical shoulder formed thereon adjacent its peri hery, which shoulder is engaged in a si arly sha ed groove formed in an arm loosely mounte upon a tongue p rojecting laterally from a hollow sleeve, which embraces the dial-carrying shaft. Rotation of the'sleeve will therefore cause the above mentioned arm to move forward and backward upon the tongue, according as the disfrom the center of the dial to the T- shaped shoulder increases or diminishes, and since said shoulder exactly follows the periphery of the dial, the pencil carried by said are designated by arm will move in a corresponding path and describe a perfect ellipse.

J-Ihe invention will be readily understood from the following detailed description, and its preferred embodiment is illustrated in the accompanying drawings, in which like parts corresponding reference numerals in the several views.

' Of the said drawings-Figure 1 is a front elevation of an ellipsograph constructed in accordance with the present invention. Fig.

2 is atop plan view thereof. Fig. 3 is a vertical section taken on the line 3-3 of Fig. 2, illustrating the disposition of the pencil carrying arm upon the tongue formed upon the shaft sleeve.

In its practical embodiment the drawing instrument includes a shaft 5 provided intermediate its ends with an elliptical dial 6, which latter has formed adjacent its periphery a vertical T-shaped shoulder 7, which exactly follows the periphery of the dial and is'therefore similar to the latter in curvature. The dial is retained in adjusted position upon the shaft by means of a collar 8, carrying a set-screw 9.

The upper portion of the shaft is embraced by a hollow sleeve 10, provided at its upper end with a milled nut 11, and having alaterally-projecting tongue 12 at its lower end, said tongue resting approximately upon the upper face of the dial. The free end of said tongue extends loosely into a socket 14formed in the inner end of a pencil-carrying This arm consists of an upper section 15, in

.which "the socket, above referred to, is

formed, and which is movable across the upper face of the dial, and a lower section-or arm 16,- which is connected to the upper section 15 by means of a transverse bolt 17,

which passes through alining transverse openings formed therein and is readily removable therefrom. The lower end of the arm carries a pencil 18.

' The sections 15 and 16, which comprise the pencil-carrying arm are provided at their inner ends with oppositely-disposed grooves 19, which mate when said sections are connected together and form a T-shape'd groove, in which the T-shaped shoulder 7 fits.

The shaft 5 is provided at its lower endwith the usual needle 20, and at its upper end with a milled nut 21, similar to the nut 11.

It will be apparent from the foregoing that when the sleeve 10 is rotated upon the shaft 5, the projection of its tongue .12 into the socketed end of the upper section of the pen- I cil-carrying arm will cause the latter to rotate therewith across the upper face of the dial. Owing, however, to the curvature of the dial and of its shoulder, and to the reception of the latter within the 'T-shaped groove formed in said arm, thelatter will be given an endwise movement backwards and forwards upon said tongue, according as the distance between the center of the dial and said shoulder decreases or increases. The lower section of the arm 14, which carries the pencil, will likewise move in a correspond ing. path, the pencil describing an ellipse as will be'obvious.

It will likewise be apparent that ellipses of varying sizes may be described owing to the jointed formation of the pencil-carrying arm. It is to be understood, moreover, that while the invention-is primarily intended as an ellipsograph various other curvilinear figures may be described thereby, since the dial me" be readily removed from its shaft and one or a different configuration substituted.

What is claimed, is

1. A drawing instrument of the class described comprising a shaft; a curvilinear dial carried thereby and provided with a vertical peripheral shoulder; an arm provided with a transverse groove adapted to receive said shoulder, said arm including a depending, pencil-carrying section; and means for rotatin'g said arm around said dial, to cause the pencil carried by said arm-section to describe a curvilinear figure. r

A drawing instrument of the class described comprising a shaft; a curvilinear dial carried thereby and provided with a vertical peri heral shoulder; a sleeve carried by said sha t and provided with a laterally-projecti'ng tongue; an arm provided with a socket and groove adapted to receive said tongue and shoulder, respectively; a pencil carried by said arm;- and means for rotating said sleeve.

3. A drawing instrument of the class described comprising a shaft; acurvilinear dial carriedthereby and provided with a vertical peri herai shoulder; a sleeve carried by said shaft and provided with a laterally-project-- ling tongue; an arm provided with asocket and T-shaped groove adapted to receive said tongue and shoulder respectively; a pencil carried by said arm and means for rotating said sleeve. a

4. An ellipsograph comprising a shaft; an

elliptical dial carried thereby and provided with a vertical T-shaped peripheral shoulder; a sleeve carried by said shaft and provided with a laterally-projecting tongue; an arm,

disposed upon the upper face of said dial, said arm having a T-shaped groove adapted to receive said shoulder, and a socketed-inner end adapted to receive said tongue; a depending arm hinged to the outer end of said first-mentioned arm and provided with a pen- I oil; and means for rotatingsaid sleeve upon said shaft to effect a simultaneous rotation of said first-mentioned arm around said dial,

and a movement backwards and forwards thereacross upon said tongue, to cause said 

